18.06.02
II. Parameters of RATAN-600 for solar study
•The PAS ideology consists in use of a parallel spectrum analysis in all frequency
range. For this purpose all
frequency range parted to the set subranges (receivers). The amplification
part of each receiver is made
in the scheme of direct amplification with output frequency filters. The input amplifiers are executed on low noise microwave
transistors. On the input of the PAS the special combined horn for all wavelengths is used. Such combined
horn has one phase center for all frequencies
with precision 1-2 angular seconds. It is provided the reception of the right
and left-hand polarization in a
modulation mode. Now the all frequency range (from 0.9 GHz to 18 GHz) covered by 7 receivers with next bands: 1) 12 - 18 GHz, 2) 8 -
12 GHz, 3) 5.5- 8 GHz, 4) 3.5 - 5.5 GHz, 5) 2.5 3.5 GHz, 6) 1.5 - 2.5 GHz, 7) 0.9 - 1.1 GHz. Each
frequency band is divided for 6-8 channels. So, the receiver complex PAS consists of 48 channels with
registration both intensity and circular polarization with about 5 % frequency resolution. As follows from the
Table 1 the main positive parameters
of RATAN-600 for solar study are:
•- The High Flux
sensitivity <0.001 s.f.u.
•- The Wide
range frequency coverage 0.92 GHz - 17.2 GHz with combined input horn.
•- The Multy
frequency instant spectral analysis with 5% frequency resolution.
•- The High
sensitivity of polarization degree
measurements <0.02 %.
•- The High
dynamic range >
• But RATAN-600 has the big
difficulty with two-dimensional
mapping and
•Sun tracking,
which we try to overcome with development of Radioheliograph regime
•(Bogod et al.,
1998) and multi-wave multi-azimuth mapping. During 2001-2002 the
•multiple
azimuth regime is realized. Now we have about 60 multiwave scans during
•4 hours (7:00
-11:00 UT) with 4 minute cadence.
